Stable isotope composition of microfauna supports the occurrence of biologically fixed nitrogen from cyanobacteria in desert soil food webs

Biological soil crusts of the arid Southwest US are habitat for a greater diversity of microfauna than soils with absent or physically disturbed crusts. The cyanobacteria of desert soil crusts fix nitrogen biologically, but it is not known whether these cyanobacteria are consumed by microfauna and a...

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Bibliographic Details
Published in:Journal of arid environments 2012-10, Vol.85, p.76-78
Main Authors: Darby, B.J., Neher, D.A.
Format: Article
Language:English
Subjects:
Animal and plant ecology
Animal, plant and microbial ecology
Biological and medical sciences
Biological soil crust
Colorado Plateau
Crusts
Cyanobacteria
Desert
Desert environments
Fauna
Food chain
Fundamental and applied biological sciences. Psychology
Invertebrates
Isotopes
Nemathelminthia. Plathelmintha
Nematoda
Nematodes
Nitrogen
Predator-prey
Soil (material)
Synecology
Terrestrial ecosystems
Tylenchidae
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Summary:Biological soil crusts of the arid Southwest US are habitat for a greater diversity of microfauna than soils with absent or physically disturbed crusts. The cyanobacteria of desert soil crusts fix nitrogen biologically, but it is not known whether these cyanobacteria are consumed by microfauna and are a significant component of the soil food web. We suspect that stylet-bearing nematodes and tardigrades are the most likely microfauna to graze on cyanobacteria, so we used natural abundance stable isotopes to test whether cyanobacteria are indeed a significant component of their diet in the field. We found that stable isotope composition of microinvertebrate biomass supports the hypothesis that cyanobacteria are a potential prey item in the food chain leading up to tardigrades and dorylaim-type nematodes in desert soils, but does not support the same hypothesis for Tylenchidae in these communities. Continued development of stable isotope methods may help to refine our understanding of feeding behaviors in belowground desert soil food webs. ► Stylet-bearing nematodes and tardigrades are the most likely microfauna to graze on cyanobacteria. ► Stable isotopes support cyanobacteria as prey for tardigrades and dorylaim-type nematodes. ► Stable isotopes do not support cyanobacteria as prey for Tylenchidae.
ISSN:0140-1963
1095-922X
DOI:10.1016/j.jaridenv.2012.06.006